Internal combustion engine control systems have been developed as steady-state, torque-based control systems. In a torque-based control system, the desired torque output of the engine is indicated by a driver input. More specifically, a driver adjusts a position of an accelerator pedal, which provides an engine torque request. The throttle is controlled to regulate air flow into the engine that provides the desired engine torque output.
Torque-based control systems determine the mass of air needed to produce the desired engine torque and determine throttle position, exhaust gas recirculation (EGR) valve position and cam phase angles based on the mass of air. Traditionally, the throttle position is commanded directly as a function of the accelerator pedal position. Commonly assigned U.S. patent application Ser. No. 10/664,172, filed on Sep. 17, 2003 and entitled Engine Torque Control with Desired State Estimation describes a method which uses the manifold filling dynamics and can initially command the throttle to a value greater than the steady-state value. As the manifold fills with air the, throttle is brought back to the steady-state position. This results in an a more aggressive partial throttle acceleration, but may lead to an unexpected feel of the vehicle to the driver by not producing the expected behavior of the throttle to a step-in change in the accelerator pedal.